About Noise Reduction

There are two other applications that perform excellent noise reduction:

1. TMPGEnc Xpress 3.0 has a noise reduction filter that both perform Spatial and Temporal noise reduction and where you can specify the intensity of both options.

2. Neat Video is a plug-in to VirtualDub, Adobe Premiere Pro and Elements and Adobe After Effects. It’s more advanced and produces excellent video. But it’s slow.

Joran

I can give you links to probably fifty different noise filters that run with different programs, along with dedicated programs for removing noise in digital still photos, removing film grain, and much more. The reason for so many filters is that "noise" is not a singular phenomenon. That is, some noise is mostly in different colors, some is monocrhomatic; some noise is the same from one picture to the next, some is quite different; some is totally unpredictable, like dust on one frame of film, yet other noise is very regular and periodic. Some noise is caused by predictable interference, like an over-modulated video signal that produces various types of bars and ripple patterns, other noise is just inherent in the type of media being used.

The spatial filters you link to are interesting, for sure, but I am not sure they would be appropriate for most video noise. I think you will find that a temporal filter that looks at multiple frames of video rather than one frame at a time will do much better with the type of noise in most video. Also, when dealing with analog video, a chroma noise filter can work wonders beyond anything you can even begin to imagine.

The "best" noise filters are those that use a motion estimation preprocessing phase that first identifies which parts of the video are supposed to be moving. Those parts that move get spatial noise reduction and those that are stationary get temporal de-noising.

If you really want to get into this, visit the forums at doom9.org.

On some of the results on this site, it kind of reminds me the Smart Blur filter in Photoshop CS2.
Some of the pics restorations are astonishing and probably couldn't be cured with this filter though.
But if you can, have a look at this Photoshop filter, it's worth it if you already haven't had a peek. Surprising.

> I can give you links to probably fifty different noise filters that run with different programs ...

Even though I probably have those links already, I concede the subject title is a tad overblown :-)

My type of noise is invariably low-light from a digital cam. I'm also currently mixing a project from a good 3-chipper and a cheap 1-chipper and I need to smooth the "color noise" from the cheap cam.

As for spatial vs. temporal noise reduction, you're probably right. The free filter from Mike Crash does great things when used in moderation.What I like most about it is that it tends to preserve the details. The one thing I cannot stand about the gaussian et al. filters is how they soften the important details (like eyes, etc). I have not explored the higher-end temporal filters, although I am somewhat familiar with the doom9 site :-)

On my current project, I've already done the stills-export -> batch smoothing -> stills-import procedure with a grain reduction filter. Much improvement but it created a new problem: You have to train the grain reduction filter on a single still, then reuse the settings on the entire clip. (Impractical otherwise.) The result is "flashes" of noise, where some frames are smooth but a few remain noisy. Visually off-putting and actually makes you notice the noise more. I'm convinced this new filter will eliminate that problem, since the default filter settings do an excellent job on a wide variety of noise problems. I'll know in a day or two.

BTW, did you check out the math from the link? Solving a PDE is a very elegant formulation of the problem and I give the author great credit for that alone. Nice PhD work.

I am going to stick to my guns and claim that this new tool is as good as it gets for enlarging the still (HDV potential from DV cameras?). Definitely superior to bicubic interpolation in all situations. I'd like to see a comparison with the fractal expanders, though.

Back to the "stills-export -> batch filter -> stills-import procedure": What does this mean for interleaved source and what settings should we be using to get the best results? Seems like an important topic that hasn't been fully explored in this forum.